The present invention relates to structural members and pertains particularly to booms and the like and method of constructing such booms for hydraulic excavators and the like.
Implement carrying booms for hydraulic excavators and the like are continuously subjected to torsional and bending loads of a high magnitude. Such booms are normally constructed of a box-like section such as that disclosed for example in U.S. Pat. No. 3,882,654, issued May 13, 1975, and U.S. Pat. No. 3,902, 295, issued Sept. 2, 1975, both issued to Yancey, and both assigned to the assignee hereof. The fabrication of such box section booms requires a considerable amount of welding. Such welding is normally the most practical way of achieving the desired structural configurations.
While such box structures as mentioned above are well suited to heavy bending loads, such structures are not well suited to torsional loads. Such torsional loads on box-section booms impose high and uneven torsional compressive and tensional stresses on certain sections of the boom structure.
In addition to the above-mentioned patents, other patents of interest in the prior art include U.S. Pat. No. 1,974,458 issued Sept. 25, 1934 to Hallquist; U.S. Pat. No. 2,910,190, issued Oct. 27, 1959 to Baas; and U.S. Pat. No. 3,186,063, issued June 1, 1965 to Dopp.